Extractor hoods have become a common feature in kitchens, due to their undisputed effectiveness in odor extraction. Current technological advances have led these appliances to much better performances than before, by increasing both operational versatility and extraction power.
There are typically two types of hoods: extraction hoods and filter hoods.
Extraction hoods extract air from the outside environment (e.g. the kitchen) and force it out of the environment from which it was drawn, e.g. out of the apartment or house.
On the other hand, filter hoods reintroduce the air they drew into the same environment, after appropriate filtering.
In certain countries, such as the United States of America, regulations have been approved (e.g. UL 507/CSA C22.2 no. 113), which impose that the environment from which the extractor hood draws air have a connection with the outside, if the flow of extracted air is higher than a given limit.
The simplest way to meet this requirement is to form a hole in the wall of the inside environment to permanently allow communication thereof with the outside environment.
Of course, such solution has a number of drawbacks, especially when the temperature of the outside environment is not optimal as compared with that of the inside environment (e.g. in Summer, when the inside environment may be conditioned, or in Winter when the inside environment may be heated).
In the light of the above described prior art, the object of the present invention is to provide an arrangement other than the one described above, to increase thermal efficiency in the environment in which the extractor hood is located.
Furthermore, the present invention affords advantages in terms of simple fabrication, greater strength, more compact design and/or higher versatility.